Issue 3, 2015

Formation of a C–C double bond from two aliphatic carbons. Multiple C–H activations in an iridium pincer complex

Abstract

The search for novel, atom-economic methods for the formation of C–C bonds is of crucial importance in synthetic chemistry. Especially attractive are reactions where C–C bonds are formed through C–H activation, but the coupling of unactivated, alkane-type Csp3–H bonds remains an unsolved challenge. Here, we report iridium-mediated intramolecular coupling reactions involving up to four unactivated Csp3–H bonds to give carbon–carbon double bonds under the extrusion of dihydrogen. The reaction described herein is completely reversible and the direction can be controlled by altering the reaction conditions. With a hydrogen acceptor present a C–C double bond is formed, while reacting under dihydrogen pressure leads to the reverse process, with some of the steps representing net Csp3–Csp3 bond cleavage. Mechanistic investigations revealed a conceptually-novel overall reactivity pattern where insertion or deinsertion of an Ir carbene moiety, formed via double C–H activation, into an Ir–C bond is responsible for the key C–C bond formation and cleavage steps.

Graphical abstract: Formation of a C–C double bond from two aliphatic carbons. Multiple C–H activations in an iridium pincer complex

Supplementary files

Article information

Article type
Edge Article
Submitted
11 Dec 2014
Accepted
21 Jan 2015
First published
26 Jan 2015
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2015,6, 2060-2067

Author version available

Formation of a C–C double bond from two aliphatic carbons. Multiple C–H activations in an iridium pincer complex

A. V. Polukeev, R. Marcos, M. S. G. Ahlquist and O. F. Wendt, Chem. Sci., 2015, 6, 2060 DOI: 10.1039/C4SC03839H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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